Knee, Bone Metastases

Question 1

Primary function of the ACL and PCL in the knee

Answer 1

Prevent anterior and posterior motion (respectively)

Act as a 4 bar linkage preventing knee rotation, and allowing for femoral rolling on knee flexion.

Question 2

Function of the patella

Answer 2

Acts as a fulcrum for knee extension from flexion by increasing the quad lever arm

Question 3

Function of the meniscus

Answer 3

To distribute load across the tibia/femur joint and maintain joint congruity. The lateral meniscus shifts more than the medial during flexion.

Question 4

Collagen type found in the menisci

Answer 4

Type I collagen (not articular cartilage)

Question 5

Q angle

Answer 5

Angle between the tibial shaft and the patella that approximates the pull of the quadriceps

Increasing the Q angle (normal is up to 15 degrees) will increase chances of a lateral displacement of the patella

Question 6

Tests used to evaluate the ACL

Answer 6

Anterior drawer/ Lachman’s

Pivot angle

Question 7

Ligaments of the knee capable of healing

Answer 7

MCL and LCL only (PCL and ACL are intra-articular)

Question 8

Ligament of the knee that is the primary restraint to lateral dislocation of the patella

Answer 8

Medial patellofemoral ligament

Question 9

Grades of Knee Injuries (3)

Answer 9

1: Damaged ligaments without laxity
2. Partial ligament tear with laxity
3. Full tear of ligament

Question 10

Three phases of ligament healing (extra-articular only)

Answer 10

1. Inflammation, clotting
2. Proliferative, increased cell density and revascularization. Collagen is disorganized
3. Remodeling, reduced cell density, alignment of collagen to forces

Note that full immobilization will impede remodeling

Question 11

Treatment required for ACL tears

Answer 11

Since ALC will not heal on its own, surgical reconstruction is needed

Question 12

Radiographic Findings in osteoarthritis (4)

Answer 12

Asymmetric joint space narrowing (RA is symmetric)
Osteophytes
Sclerosis
Subchondral cysts

Question 13

Clinical presentation of osteoarthritis

Answer 13

Typically affects knee or large joints, or hand

Pain is worst as day progresses (best in morning or on weekends)

Knee is the most commonly affected joint

Question 14

Risk factors for developing OA of any joint (5)

Answer 14

Genetics
Trauma or misalignment of joint (especially hip problems in children)
Obesity or increased loads
Meniscectomy
Joint instability such as an untreated ACL tear which also tears the meniscus

Question 15

Treatment options fo OA

Answer 15

Decrease loads/ joint use via insoles, low impact exercise, or work limitations
Lose weight
Improve ROM with stretching exercises
Improve strength and balance

If needed, arthroscopy and meniscectomy, but typically not any more effective than PT

Question 16

Cause of patellofemoral pain syndrome

Answer 16

Develops from sudden increases in activity or training errors

Question 17

Presentation of patellofemoral pain syndrome

Answer 17

Diffuse, aching, anterior knee pain

Question 18

Motion most associated with meniscal tears

Answer 18

Twisting of the knee in young patients or degeneration in old

Question 19

Clinical presentation of meniscal tear

Answer 19

Joint line pain and tenderness
Pain increases with twisting or squatting
Knee may click or catch while binding/extending

Question 20

Treatment of meniscal tears

Answer 20

Should get an MRI to evaluate extent of damage
Menisci may heal if only torn in vascular outer third
Observation appropriate in older individuals
Cartilage transplant (after meniscectomy) or surgical correction in athletes

Question 21

Motions associated with ACL tear

Answer 21

Jumping, pivoting, landing

Most are not associated with sports

Question 22

Imaging needed for ACL tears

Answer 22

MRI to assess damage and determine if a meniscal tear is also present (50%)

Question 23

Treatment used for ACL tears

Answer 23

Sedentary: non-operative
Active: ACL reconstruction (will not heal), using harvested tissue from achilles or hamstrings

Question 24

Most Common soft tissue sarcomas in adults

Answer 24

Liposarcoma

Undifferentiated fibrosarcoma

Question 25

Most common ST sarcomas in children

Answer 25

Rhabdomyosarcoma | Synovial sarcoma

Question 26

Imaging studies typically used in soft tissue sarcomas

Answer 26

X-ray to assess bone involvement and periosteal reaction MRI to assess tumor shape and involvement Chest CT to examine for lung involvement

Question 27

Most common malignant bone tumors of children

Answer 27

``` Osteogenic sarcoma (blastic) Ewing's sarcoma (lytic) ```

Question 28

Most common benign bone lesions in children

Answer 28

Unicameral bone cysts | Fibrous dysplasia

Question 29

Undifferentiated fibrosarcomas

Answer 29

MALIGNANT AGGRESSIVE soft tissue sarcoma seen in adults that commonly involves the lungs

Question 30

Liposarcoma

Answer 30

Less aggressive (than undiff fibrosarcoma) ST sarcoma that can spread to the peritoneum or abdominal viscera

Question 31

Location of most synovial sarcomas

Answer 31

Hands and feet (but not derived from synovial cells)

Question 32

Treatment options for unicameral bone cysts

Answer 32

``` Resolve on own Only use treatment if painful or persistent after skeletal maturity. Cysts may recur. - Bone graft - Injection - Cryotherapy ```

Question 33

Pathologic presentation of fibrous dysplasia

Answer 33

skeletal deformity with propensity for fracture or limb bowing (including arms)

Question 34

Albright's syndrome

Answer 34

Fibrous dysplasia combined with: - Precocious puberty - Cafe au lait

Question 35

Histologic and radiographic findings in fibrous dysplasia

Answer 35

Lytic lesion with ground glass | Small segments of bone in a fibrous stroma

Question 36

Significant finding in Ewing's sarcoma

Answer 36

Blue cells that stain positive for glycogen

Question 37

Treatment options for Ewing's sarcoma

Answer 37

If bones are expendable: give surgery and chemotherapy | If bones are not expendable: give radiation only with similar results

Question 38

Most common locations of cancer metastasis to bone

Answer 38

Pelvis, spine, femur, humerus

Question 39

Factors influencing treatment options for patients with malignant bone metastases

Answer 39

Amount of pain Size of lesion Risk of having fracture (should always stabilize PRIOR to radiation)

Question 40

Lifespan prognosis of achondroplasia and Osteogenesis imperfecta

Answer 40

``` Achondro = normal BBD = shortened ``` Both are AD disorders

Question 41

Amino acid missing in osteogenesis imperfecta

Answer 41

Lacking glycine in collagen triple helix